The Gawler Range Volcanics are an extensive series of subaerial felsic lavas and ignimbrites, which crop out on the central Gawler Craton. Twenty seven sites within the southern Gawler Range Volcanics were inspected to determine their potential to supply stone for use in the porphyry ornamental stone industry. The volcanic rocks of the Gawler Ranges in general are highly jointed, with dominant regional and outcrop scale joint sets trending northeast-southwest and southeast-northwest. These are accompanied by lesser, finely cross-cutting joints. Spectacular examples of local columnar jointing of dacitic lavas exist within the southern Gawler Ranges, but rocks examined at such sites have no potential for use in the porphyry industry, due to their overmuch jointed nature, and the need for conservation of such exposures in order to realise their tourism potential. However, a related Hiltaba Suite porphyritic granite occurring at Yarna is unusually massive and relatively joint-free, and offers clear potential for large block extraction, although its excessive distance away from existing infrastructure may make the stone uneconomic to quarry.